True enough. :)
So what's the point of the thought experiment?
Pedagogy. Just like with the exercises you find in physics textbooks.
As it stands, it has no "stationary object," no anchor or criterion according to which its phenomena can be compared and judged. JMHO FWIW
When we speak of a "stationary object" it is understood that this is not because the object meets some universal standard for being "stationary" (there is none) but because the object is stationary WRT to some inertial frame. The Sun is stationary WRT an inertial frame to a close enough approximation for the purpose of emphasizing the empirical difference between a real orbit as viewed from an inertial frame and an apparent orbit due to viewing a stationary object from a rotating frame. In the context of the merry-go-round experiment, the same could be said of the "stationary" target standing still on the Earth. Does this clarify things?
Yes it does, and thank you Zero Sum.
I can recognize the "pedagogical value" of such exercises. My initial reaction was motivated by concern that thought experiments be as "realistic" as possible. Yet there are all kinds of "thought experiments" going on wasting a whole lot of time and energy IMHO proposing things that have not got the least chance of being tested (e.g., panspermia theory and a raft of parallel universe cosmologies). It seems to me at the end of the day the insights of science must map to Reality. But some of these "thought experiments" seem to be constructing "second realities." They might be fun to think about, but: How on earth could they possibly be "tested?"
Meanwhile, there are plenty of "interesting" unanswered questions a bit closer to home. Such as: What is Life? Actually, it seems it's been the mathematicians and physicists who have been taking the lead on this question, from the 1930s forward (e.g., Ervin Bauer, Nicholas Rashevsky, Robert Rosen). They worked independently of each other, but their common object was to develop a mathematically-based theoretical biology. I'm just beginning to discover their work and am finding it fascinating. Suffice it to say that so far, their entire approach and findings have been mostly ignored by both the physics and biology communities.
Anyone interested in taking a look at these ideas, I highly recommend Robert Rosen's Life Itself: A Comprehensive Inquiry into the Nature, Origin, and Fabrication of Life.
I guess you and I weren't really speaking about the same thing from the get-go.... Sorry!
Thank you kindly for your reply!